Electrostatic method of applying flock to a paint roller sleeve



Nov. 19, 1968 I POWER SUPPLY F. B. BURNS ETAL ELECTROSTATIC METHOD OF APPLYING FLOCK TO A PAINT ROLLER SLEEVE Filed Dec. 3, 1964 POWER SUPPLY POWER SUPPLY 631% ,yemlagaeao United States Patent ELECTROSTATIC METHOD OF APPLYING FLOCK TO A PAINT ROLLER SLEEVE Fredrick B. Burns, South Milwaukee, and Erik Henningsen, Milwaukee, Wis., assignors to EZ Painti- Corporation, a corporation of Delaware Filed Dec. 3, 1964, Ser. No. 415,624 3 Claims. (Cl. 117-17) ABSTRACT OF THE DISCLOSURE A flocked paint roller sleeve having the flock fibers generally at a uniform acute angle with respect to the sleeve surface, in one form inclined peripherally and in another inclined axially of the roller. A method and apparatus for manufacturing such sleeves provides a radial electrostatic field and effects relative movement between the roller sleeve and fibers which has a unidirectional component peripheral of the sleeves.

This invention is concerned with a paint applicator, more particularly a paint roller sleeve, and with a method and apparatus for manufacture of the applicator.

It has in the past been proposed to manufacture paint roller sleeves by a flocking process in which short fiber particles are electrostatically deposited on a cylindrical base member. See, for example, Thackara et al. 2,806,803. We have found, however, that sleeves manufactured in a manner similar to that of the Thackara et al. patent are unsatisfactory. When painting with such a sleeve, the roller will wobble back and forth or walk across the surface at an angle to the direction the roller is moved by the painter. The finish imparted to the surface is unsatisfactory. Furthermore, such a roller sleeve is rather diificult to use. We believe this action is due to the orientation of the fibers in different directions with respect to the surface of the base member. This gives the roller sleeve an irregular nap and the resiliency of the fibers apparently causes the roller to move longitudinally as it is used.

A principal objective of this invention is to provide a.- fiocked paint applicator in which the fibers have a generally uniform orientation with respect to the base, preferably extending from the base at an angle rather than normal thereto, overcoming the difficulties described above.

One feature of the invention is the provision of a paint roller sleeve comprising a cylindrical base having fibers secured to the outer surface thereof, each fiber extending outwardly from the base and generally at an acute angle with respect to a plane tangent to the base and the orientation of the fibers with respect to the associated plane being substantially the same. In accordance with one aspect of the invention the fibers lie in generally radial planes, at right angles to the longitudinal axis of the base and each forms an acute angle with respect to the related tangent plane. In another form of the invention the fibers lie in planes extending longitudinally of the base and passing through the longitudinal axis.

Another feature of the invention is the provision of a method for flocking a paint applicator in which an electrostatic field is established with respect to the applicator base and movement is effected beween the base and flock fibers, the relative movement being unidirectional. More specifically, flock fibers are deposited on the surface of a roller sleeve base by effecting relative movement between the fibers and base which has a unidirectional component peripherally of the base. A further feature of the method is that the flock fibers are dropped past the roller base through quiescent air.

3,411,931 Patented Nov. 19, 1968 Still another feature of the method of flocking a paint roller sleeve is that the sleeve is rotated in a horizontal plane and the fibers are dropped along one side thereof. Alternatively the sleeve is mounted in a vertical plane and the particles are dropped past it.

Yet a further feature of the invention is the provision of an apparatus for depositing fibers on a sleeve in which the fibers are dropped from a source past a sleeve supporting spindle with means establishing an electrostatic field between the spindle and electrodes adjacent thereto.

Further features and advantages of the invention will readily be apparent from the following specification and from the drawings, in which:

FIGURE 1 is an end view of a paint roller sleeve embodying the invention;

FIGURE 2 is a diagrammatic elevation of an apparatus for manufacturing the sleeve of FIGURE 1;

FIGURE 3 is a view taken from the left of FIGURE 2;

1 FIGURE 4 is a longitudinal section through a modified s eeve;

FIGURE 5 is a diagrammatic illustration of an apparatus for manufacturing the sleeve of FIGURE 4;

FIGURE 6 is a diagrammatic view of another apparatus for manufacturing applicators embodying the invention;

FIGURE 7 is a perspective view of another paint applicator embodying the invention; and

FIGURE 8 is an edge view thereof.

In the prior art as illustrated in the Thackara patent, adhesive coated cylindrical base members for paint rollers are moved on supports through a flocking chamber in an upright position. Flock entrained in air is blown into the chamber through two nozzles, one on either side of the path of the adhesive coated cores. And electrostatic field extends between the base supports and electrodes along the inner walls of the housing. Most of the fibers impinge on the cylindrical base members from two different directions and as a result do not have the same orientation or angular relation to the base. This gives rise to the unsatisfactory painting characteristics described above.

The apparatus and method disclosed herein produce a flocked paint applicator which does not have the erratic painting characteristics of other flocked applicators. It is our theory that the application of the flock material in a manner in which the fibers have substantially the same orientation with respect to the base eliminates the tendency of the applicator to move laterally during use.

In FIGURE 1 of the drawings, a paint roller sleeve 10 has a cylindrical base 11 which may be formed of a spiral wrapped multi-ply paper impregnated with a waterproofing substance. A layer 12 of adhesive covers the outer surface of the sleeve. Flock fibers 13 have their ends embedded in the adhesive 12 and extend outwardly from the sleeve surface. The fibers 13 each lie in a generally radial plane at right angles to the longitudinal axis of the tubular base 11 and form an angle of the order of 15 with respect to an extension of the radius, or an angle of with respect to a plane tangent to the surface of the base. Substantially all of the fibers are oriented so that they extend generally in the same relative direction with respect to the surface of the base.

The fiber material, diameter and length are determined primarily by the specific use for which the roller sleeve is intended. A fiber suitable for enamels may not he satisfactory for a water base paint, for example. Preferably, however, the fibers are of a synthetic plastic material, as nylon.

An apparatus for depositing fibers on the base in the manner shown in FIGURE 1 is illustrated in FIGURE 2. The cylindrical base 11 has its outer surface coated with a suitable adhesive and is mounted on a rotating conductive spindle located between conductive electrode panels 16 and 17. A flock sifter 18 is located above the spindle and has a screenlike or foraminous bottom 19 through which flock fibers 13 are discharged, to fall under the influence of gravity between the spindle and the electrodes. A reciprocating blade 20 agitates the fibers in the sifter and insures a continual and relatively uniform fiow to the flocking enclosure. A power supply 21 has one terminal connected with conductive spindle 15 and the other connected with ground 22 and thus to grounded electrodes 16 and 17.

The fibers drop from the grounded sifter 18, acquire a charge and are attracted to the charged spindle inside base 11. Some of the fibers are charged as they leave the sifter while others fall against electrode 17, acquire a charge and are then attracted to the spindle. This attraction causes the ends of the fibers to be embedded in the layer of adhesive on the outer surface of the sleeve with the fibers extending outwardly therefrom. To insure that all the particles are oriented in the same direction, the movement of the particles is directed peripherally around the spindle and base in only one direction. In the apparatus of FIGURE 2, this is achieved by providing a bafile element 23 which is a portion of grounded conductive electrode 16. The bafiie extends above at least one-half of the spindle 15 and roller sleeve base 11 and along the length of the base. Bafile 23 prevents fiock fibers from traveling counterclockwise about base 11 and being attrached to the base with an orientation different from those which pass clockwise about the base. Rotation of the spindle exposes all portions of the base to the fiow of fibers and insures uniform coating with the fibers.

The air within the flocking enclosures is preferably maintained in a quiescent condition so that the pattern of the falling fibers is not disturbed.

Flock fibers which are not deposited on the sleeve as they pass downwardly between the spindle and electrodes are received in a pan 24 below the electrodes. Flock particles may be returned from the pan 24 to sifter 18 if desired. For example, a blower (not shown) may continuously recirculate the particles.

After a sleeve is fully coated with flock fibers, the adhesive is cured in a suitable manner, as by placing the sleeve in an oven.

A specific mechanism for rotating spindle 15 is not illustrated herein. Any suitable mechanism may be used. Such, for example, as that shown in the Thackera et al. patent where the spindle is moved on a continuous chain conveyor and carries a spur gear at one end which engages a fixed rack to effect rotation.

Turning now to FIGURES 4 and 5, another form of roller sleeve embodying the invention is illustrated. Here, the fibers 31 lie in planes which extend longitudinally of the cylindrical base 32 and pass through the longitudinal axis of the base. The fibers 31 are oriented in the same direction as can be seen in FIG- URE 4, and have an angle of the order of 15 to 20 with respect to a radial plane transverse to the axis or of 75 to 70 with respect to a plane tangent to the surface of the base. Again, the uniform orientation of the fibers eliminates erratic operation and assures a smooth, even application of paint.

The apparatus illustrated in FIGURE 5 applies the flock fibers in a manner which produces the roller sleeve 30 of FIGURE 4. Cylindrical sleeve base member 32 is mounted on a conductive spindle 35 which extends vertically between grounded conductive electrodes 36 and 37. The flock fibers are discharged through the bottom of the sifter 38 as blade 40 moves back and forth. As in FIGURE 2, the conductive spindle 35 is connected with a terminal of power supply 42, the other terminal of which is grounded. The electrostatic field set up between the spindle and electrodes 36 and 37 attracts the fibers and their ends are embedded in the adhesive covering of the sleeve base. As a result of the downward movement of the particles and the effect of gravity, the fibers hang downwardly from a horizontal plane imparting the uniformly oriented angular relationship illustrated in FIG- URE 4. Again, the majority of the fibers are not randomly applied to the base, but are oriented uniformly.

Spindle 35 need not be rotated if it is positioned under sifter 38 in such relation that the flow of fibers is generally uniform all the way around the sleeve.

In this embodiment of the invention the flock fibers have no component of movement peripherally of the sleeve base 32, but travel longitudinally with respect thereto. For the purpose of this invention the concept of unidirectional peripheral movement discussed above and incorporated in the claims is defined as including axial or longitudinal movement where the peripheral component is zero.

The fibers which pass by the sleeve are collected in grounded pan 43 and may be returned to sifter 38 in a suitable manner.

FIGURE 6 illustrates another apparatus embodying the invention. Spindle is positioned in a generally horizontal plane between grounded electrodes 51 and 52. The spindle is connected with a suitable power supply 53 establishing an electrostatic field between the spindle and the electrodes. The flock fibers 54 are deposited from a hopper 55 on a conveyor belt 56 which travels beneath the spindle 50. As the particles pass beneath the spindle, they are drawn upwardly by the electrostatic field and deposited on the adhesive coated surface of roller sleeve base 57 which is mounted on the spindle. An agitator bar 58 located beneath the conveyor belt 56 may be rotated to disturb the fibers subjected to the influence of the field which then draws them upwardly to be deposited. A portion 59 of electrode 51 extends beneath spindle 50 and serves as a baffle to direct the fibers to the right hand side of the spindle so they have a unidirectional component of motion with respect to the sleeve base. As in FIGURE 2, the spindle is rotated to insure uniform distribution of the fibers.

FIGURES 7 and 8 illustrate another form of the inven tion in which the applicator is fiat rather than cylindrical. A flat applicator may be useful in applying paint in corners or to small surfaces which cannot readily be coated with a roller. The applicator has a flat planar base 65 to which are secured fibers 66, as by an adhesive layer 67. As in the sleeve-type rollers, the fibers 66 are deposited on the base at an acute angle (of the order of 75 with respect to the surface of the base, for example). As best seen in FIGURE 7, substantially all the fibers have the same orientation with respect to the base so the applicator will move smoothly across the surface to be coated.

We claim:

1. The method of applying flock fibers to a cylindrical paint roller sleeve having an adhesive outer surface, which comprises: mounting a sleeve for rotation about its longitudinal axis with its longitudinal axis in a generally horizontal plane; rotating said sleeve about said axis; establishing an electrostatic field extending generally radially of said sleeve; and dropping flock fibers in said field past only one side of said sleeve whereby the ends of the fibers are embedded in the adhesive and the fibers are orientated so that they extend generally in the same relative direction with respect to the surface of the sleeve.

2. The method of applying fiock fibers to a cylindrical paint roller sleeve having an adhesive outer surface, which comprises: mounting a sleeve for rotation about its longitudinal axis with its longitudinal axis in a generally horizontal plane; rotating said sleeve about said axis; establishing an electrostatic field extending generally radially of said sleeve; and providing fibers below the sleeve which are electrostatically attracted upwardly toward only one side of said sleeve whereby the ends of the fibers are embedded in the adhesive and the fibers are oriented so that they extend generally in the same relative direction with respect to the surface of the sleeve.

3. The method of applying flock fibers to a cylindical paint roller sleeve having an adhesive outer surface which comprises: mounting a sleeve with its longitudinal axis in a vertical plane; establishing an electrostatic field extending generally radially of said sleeve; and dropping flock fibers past said sleeve, in a uniform pattern around the sleeve whereby the ends of the fibers are embedded in the adhesive and the fibers are oriented so that they extend generally in the same relative direction with respect to the surface of the sleeve.

References Cited UNITED STATES PATENTS 2,047,525 7/1936 Thode .11717 2,217,444 10/1940 Hill .117-17 6 Ransburg et a1. 117-17 X Hiers ll7l7 Adams 29120 Smith ll7l7 X Hirschberger ll7l7 White 29-120 X Stahl 117-17 X Thackara et al. ll7l7 Lemelson 156-72 FOREIGN PATENTS 9/1949 Australia.

WILLIAM D. MARTIN, Primary Examiner.

15 E. J. CABIC, Assistant Examiner. 

